This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The specific aim of this bioanalytical project is to: 1) develop capillary electrophoresis-based assays capable of resolving complex mixtures of carbohydrates and 2) apply the methodologies to analyze nutrient availability in a gastrointestinal ecosystem of biomedical importance. More specifically, the in vivo nutrient content of mouse intestinal mucus, which is the habitat for infecting E. coli, will be examined. This project will be a collaborative effort between Dr. Tyrrell Conway of the University of Oklahoma and Dr. Tim Smith at Southeastern Oklahoma State University. Mutational analysis in mouse colonization studies revealed several sugars that appeared to be important for E. coli to colonize. An important extension of these findings is to use chemical methods to prove these sugars are available in mucus and to determine E. coli's in vivo order of preference for the individual mucus-derived sugars. In this study, capillary electrophoresis was utilized to monitor the carbohydrate and amino acid metabolism of various E. coli strains using both in vitro and in vivo models. The goal is to determine the actual nutrient availability to enteric bacteria in the intestine. This collaboration is providing a deeper understanding of how gastrointestinal pathogens acquire the nutrients necessary to infect their host and begin the disease process and should build on the knowledge of this model system.